.banner{
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  margin: 20px auto;
  width: 600px;
  height: 400px;
  border: 3px solid #333;
  position: relative;
  overflow: hidden;
  ul {
    position: absolute;
    width: 3600px;
    height: 400px;
    list-style: none;
    left: -600px;
    li {
      float: left;
      width: 600px;
      height: 400px;
      img {
        display: block;
        width: 600px;
        height: 400px;
      }
    }
  }
  ol {
    list-style: none;
    position: absolute;
    right: 10px;
    bottom: 10px;
    background-color: pink;
    padding: 10px;
    li {
      float: left;
      width: 20px;
      height: 20px;
      background-color: #666;
      border-radius: 50%;
      margin-left: 20px;
      &:first-child {
        margin-left: 0;
      }
    }
  }
  .atv {
    background-color: #008c8c;
  }
  .btn {
    color: black;
    font-size: 30px;
    width: 30px;
    height: 35px;
    position: absolute;
    font-weight: 900;
    margin-top: -10px;
    top: 50%;
    line-height: 35px;
    background-color: rgba(255, 255, 255, 0.5);
  }

  .left {
    left: 10px;
  }

  .right {
    right: 10px;
  }
}
